An object of obsessive, usually exaggerated fear or anxiety: "Boredom, laziness and failure . . . These bugaboos, magnified by imagination, keep [the workaholic] running"(Dun's Review).
A recurring or persistent problem: "the bugaboos that have plagued vision systems: high price and slow throughput"(Lawrence A. Goshorn).
[buhg-uh-boo] 
əˌbu